Studies on reproductive performance in pure and cross bred dairy-cattle.

摘要

Age at first calving, first service period and calving interval were recorded for 50 Sahiwal (S), 50 Sahiwal X Jersey (S X J), 50 Sahiwal X Holstein (S X H) and 50 Desi X Holstein (D X H) cows from a herd at the State Livestock Farm, Chak-Ganjaria,Lucknow and at an unorganized farm in Kanpur (for D X H only). Average age at first calving was 1138.24?1.92, 1006.45?4.32, 1076.11?3.62 and 1220.16?1.46 days in S, J X S, S X H and D X H cows, respectively. Respective values for first service periodwere 165.12?.3, 109.74?.02, 132.02?1.72 and 188.21?1.94 days and for calving interval were 456.30?2.13, 392.60?5.47, 420.70?2.23 and 482.54?.93 days.